Title

Does temperature affect the elastic potentials of a basketball?

Broad Question

How high does a basketball bounce.

Specific Question

Does temperature affect the elastic potential of a basketball?

Independent Variable:

temp

Dependent Variable:

height

Variables That Need To Be Controlled:

the ball

Hypothesis

if the ball is colder it wont bounce as high.

Graph of Hypothesis

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General Plan

I will do this experiment in my garage. I will be the only one in my experiment. I will do 3 trials. I will record my info. I will make a document.

Experimental Design

I will do the experiment in my garage. I will be the only one in my experiment.
I will do three trials. I will record my data.

Materials list

Fire - heat source

Two basketballs
Meter stick
Ladder
Snow

detailed procedure

1. Put a basketball in snow and by a fire
2. Set up a ladder in my garage 10ft.
3. tape the meter sticks on the wall
4. go grab both of the basketballs
5. climb up the 10foot ladder
6. Drop the balls from 10ft.
7. record bounce height

Resources and Budget Table

Data Table

	t1	t2	t3	t4	t5

cold ball

hot ball

Background Research

Everyone has played with balls that bounce, but few people truly understand the physics behind a bouncing ball. When you hold a ball above a surface, the ball has potential energy. Potential energy is the energy of position, and it depends on the mass of the ball and its height above the surface. The formula for gravitational potential energy is PE = mgh where m is the mass of the ball measured in kg, g is the gravitational acceleration constant of 9.8 m/se c2 , and h is the height of the ball in m. As the ball falls through the air, the potential energy changes to kinetic energy. Kinetic energy is energy of motion. The formula for kinetic energy is KE=1/2 mv 2, where m is the mass in kg and v is the velocity in m/sec 2. Both potential and kinetic energy have units of Joules (J).
As the ball falls through the air, the Law of Conservation of Energy is in effect and states that energy is neither gained nor lost, only transferred from one form to another. The total energy of the system remains the same; the potential energy changes to kinetic energy, but no energy is lost. When the ball collides with the floor, the ball becomes deformed. If the ball is elastic in nature, the ball will quickly return to its original form and spring up from the floor. This is Newton's Third Law of Motion- for every action there is an equal and opposite reaction. The ball pushes on the floor and the floor pushes back on the ball, causing it to rebound.
On a molecular level, the rubber is made from long chains of polymers. These polymers are tangled together and stretch upon impact. However, they only stretch for an instant before atomic interaction forces them back into their original, tangled shape and the ball shoots upward.
You may be wondering why the ball does not bounce back to its original height. Does this invalidate the Law of Conservation of Energy? Where did that energy go? The energy that is not being used to cause motion is changed to heat energy or sound energy. After playing a game of tennis or racquetball, you will notice that the ball is warmer at the end of the game than at the beginning because some of the motion energy has been changed to heat energy. Because bouncy balls have tightly linked polymers, most of the energy is transferred back to motion so little is lost to heat or sound energy, and the ball bounces well. This is the way the Happy Ball behaves.
The Sad Ball has different characteristics. When it is dropped from the same height onto the same surface, it does not bounce even though it has been given the same amount of potential energy as the Happy Ball. It does not bounce because it is made up of a different material. Unlike the Happy Ball which is made of Neoprene, or common rubber, the Sad Ball is made of Norbonene. On a molecular level, Norbonene is different from Neoprene because Norbonene's polymers are more loosely arranged and rub together more when the ball deforms. This additional movement results in motion being converted to heat energy; instead of the ball bouncing, it gets warm. There are several ways to make the Sad Ball happy. One way is to change the temperature of the ball. When the Happy Ball is cooled, its molecules are not as flexible, causing the ball to rebound a smaller distance. When the Sad Ball is cooled, the Norbonene polymer does not deform as much, so less energy is converted to heat energy and the ball bounces. If the Sad Ball is heated, the same process occurs and the ball bounces.
Neoprene and Norbonene have many uses besides bouncy balls. Neoprene is commonly used for wire and cable jacketing, automotive gaskets, seals, hoses and tubes, power transmission belts, foamed wet suits, latex gloves and balloons, as waterproof membranes, and for asphalt modification. Neoprene is flexible in its uses because it resists degradation from the sun, ozone, and weather. It performs well when in contact with oil and chemicals and is useful over a wide temperature range. It also resists burning better than exclusive hydrocarbon rubbers and resists damage caused by flexing and twisting. Doping of the Neoprene polymer allows for more versatility and optimal performance. Norbonene rubber has impact absorption uses. It is used as a damping material in shock absorbers and for the protection of conveyor mechanisms. It is used as a padding material in items such as body armor, helmets, sports gloves and mitts, and in the soles of shoes. It is also widely used as an industrial packing material. Stereo speakers make use of Norbonene to minimize resonance and external vibration.
Happy and Sad Balls behave differently in a variety of situations. They roll down a ramp at different speeds, they emit sound waves at different decibels, and they bounce different heights on different surfaces. They can be compressed dissimilar amounts when the same force is applied and they are different densities, so they sink in different solutions at variable rates.
Allow students to play with the balls for a while and experiment with dropping and rolling the balls to allow them some time to compare and contrast the behavior of the balls and for creative ideas to occur. The time frame for completing the lab is approximately 90 minutes, although this can be modified by reducing the temperatures tested to three instead of five, or splitting the class into 5 groups where each group tests only one temperature and then places their results on a class data table. Achieving exact temperatures is unnecessary; near 00C and near 1000C are easy to get through the use of ice and by boiling water. Room temperature is near 200C. Two other temperatures, one lower than room temperature and one higher should be used to more completely explore Happy and Sad Ball trends.

Photo List